Apparatus for opening the flaps of a container and removing debris therefrom

ABSTRACT

An apparatus for opening and spreading the top flaps of a carton containing packaged articles such as bottles, and for cleaning the carton after the flaps are opened. The carton containing the articles is moved along a conveyor and the sides of the carton are engaged by pressure members which deform the sides and pivot the flaps, if closed, to a partially open position. The carton then passes beneath a vacuum duct, which acts to raise the flaps. After the flaps have been raised, the carton moves into engagement with a spreader unit which spreads the flaps laterally outward. With the flaps in the spread position, the carton is then conveyed beneath a second vacuum duct which acts to draw lightweight debris from the carton.

0 United States Patent 1 3,649,993 Sauer [451 Mar. 21, 1972 [s41 APPARATUS FOR OPENING THE 2,997,833 8/1961 Nigrelli et al. ..53/3s2 FLAPS OF A CQNTAINER AND 3,224,166 12/ 1965 Johns et al. ..53/382 REMOVING DEBRIS THEREFROM Primary Examiner-Walter A. Scheel [72] Inventor: Henry Sauer, Honolulu Assistant Examiner-C. K. Moore Q AuorneyAndrus, Sceales, Starke & Sawall [73] Assigneez Jos. Schlitz Brewing Company, Milwau- Ree, 57 ABSTRACT [22] Filed: June 1970 An apparatus for opening and spreading the top flaps of a car- A L N 47,500 ton containing packaged articles such as bottles, and for [21] pp 0 cleaning the carton after the flaps are opened. The carton containing the articles is moved along a conveyor and the sides of [52] U.S.Cl ..15/304, 15/306 B, 53/382 the carton are engaged by pressure members which deform [51] Int. Cl. ..A47l 25/00 the sidesv and pivot the flaps, if closed, to a partially open posi- [58] Field of Search ..15/301,303, 304,306 B; tion The carton then passes beneath a vacuum duct, whic 5 3 3 acts to raise the flaps. After the flaps have been raised, the carton moves into engagement with a spreader unit which spreads 56] References Cited the flaps laterally outward. With the flaps in the spread position, the carton is then conveyed beneath a second vacuum Nl AT S NTS duct which acts to draw lightweight debris from the carton.

2,620,961 12/1952 Wahl et al. 15/306 BX 19 Claims, 9 Drawing Figures PATENTED MR2] I972 SHEET 1 OF 3 ZLMMVQA Attorneys sum 2 UF 3 PATENTEDMARZI I972 INVENTOR. Henry Souer Attorneys PATENTEDMARZI 1972 $649,993

sum 3 {1F 3 m m V m Henry Souer Attorneys APPARATUS FOR OPENING TI-IE FLAPS OF A CONTAINER AND REMOVING DEBRIS THEREF ROM The invention relates to an apparatus for opening the top flaps of a fiber board or corrugated carton which contains empty packaged articles, such as bottles, and for cleaning the carton of lightweight debris prior to removing the bottles.

The conventional beer case is formed of fiber board or corrugated paper and the top is enclosed by a pair of flaps which are hinged along the side edges of the carton. When the beer case containing empty bottles is returned to the brewery, the cases are normally introduced onto a conveyor system and each case initially passes through a device which is adapted to pivot the flaps upwardly and hold the flaps open so that the bottles can be automatically withdrawn from the case by a bottle removing mechanism. In the past various devices have been employed to open the flaps of the case and the conventional device consisted of a series of vacuum cups which were moved into engagement with the flaps. After the vacuum cups were pressed into engagement with the flaps a linkage pivoted the cups to thereby move the flaps to the open position and expose the bottles. The conventional devices used for opening the flaps have been relatively expensive due to the rather complex linkages involved and were relatively slow operating due to the number of specific operations involved in the flap opening procedure.

The present invention is directed to an apparatus for opening the top flaps of a beer case or carton and subsequently cleaning the carton of lightweight debris prior to removal of the bottles. More specifically, the apparatus comprises a conveyor and the cases are moved along the conveyor and initially pass between a pair of spaced flap closing members which act to pivot the side flaps inwardly in the event the flaps are spread apart as the case enters the unit. The case then passes between two series of rollers which apply pressure to the opposite side walls of the case, and, in the event the flaps are fully closed, serves to pivot the closed flaps upwardly and release the flaps from the fully closed position. The case moves beneath a vacuum duct which creates a vacuum of sufficient intensity to pivot the flaps upwardly, and after raising of the flaps, the case is moved through a spreader unit that engages the partially opened flaps as the case continues along the conveyor and spreads the flaps outward so that the flaps are located laterally of the side walls of the case.

With the flaps in the spread position the case is then moved beneath a second vacuum duct which acts to remove lightweight debris, such as napkins, straws, cigarette butts, and the like, from the case. Following removal of the debris, the case is moved along the conveyor system to the mechanism which removes the bottles from the case.

The invention provides a continuous mechanism for automatically opening the flaps on the case or carton, spreading the flaps outwardly so that they extend laterally of the case and then removing lightweight debris from the case prior to removal ofthe bottles.

The mechanism is adjustable for different heights and widths of cases and the inlets to the vacuum ducts can be corresponding raised and lowered depending on the particular height of the case passing along the conveyor line.

Other objects and advantages will appear in the course of the following description.

The drawings illustrate the best mode presently contemplated of carrying out the invention.

In the drawings:

FIG. 1 is a side elevation of the apparatus of the invention;

FIG. 2 is a transverse section taken along line 2-2 of FIG.

FIG. 3 is a section taken along line 33 of FIG. 1;

FIG. 4 is a plan view of the apparatus;

FIG. 5 is an enlarged fragmentary side elevation of the hood and ducts;

FIG. 6 is an enlarged side elevation of the end flap holder;

FIG. 7 is an end view of the end flap holder shown in FIG. 6;

FIG. 8 is an enlarged view of the roller; and

FIG. 9 is an enlarged view of the guide rail.

The drawings illustrate an apparatus for opening and spreading the flaps on a carton or case and subsequently removing lightweight material from the opened case. The apparatus, in general, includes a conveyor unit 1 and the cases or cartons 2 are moved continuously along the conveyor unit in the direction of the arrow in FIG. 1. As the cases move along the conveyor, they engage a flap opening unit 3 which acts to raise the flaps of the case to a partially open position. After the flaps have been raised or opened, the case passes beneath a flap spreading unit 4 which functions to spread the flaps laterally outward so that they project laterally beyond the side walls of the case, After the flaps have been spread, the case passes beneath a vacuum cleaning unit 5 that serves to remove lightweight debris from the open case. The case 2 then continues on the conveyor 1 through the brewery to a station where the bottles are automatically removed from the case.

The conveyor 1 is of conventional construction and includes a series of legs 6 which support a generally horizontal frame 7. An endless belt 8 is trained about an idler roller 9 at the front end of the conveyor and over a drive roller 10 located at the rear end of the conveyor. The belt 8 is supported in its path of travel by a series of transverse rollers 11 which are journaled between the channel shaped side walls 12 of frame 7. The cases 2 are conveyed on the endless belt 8 through the system.

To drive the belt, a motor 13 is mounted on a platform 14 connected to the conveyor frame 7, and the motor drive shaft 15 carries a sprocket 16 that is connected by chain 17 to a sprocket 18 carried by the shaft 19. Roller 10 is also mounted on shaft 19. Thus, rotation of the motor drive shaft 14 acts through the chain drive to rotate the drive roller 10 and thereby move the belt 8 in endless travel. A conventional takeup mechanism 20 is associated with the belt and is carried by the frame 7 and serves to maintain the proper tension on the belt.

To guide the cases 2 in movement on the conveyor a pair of guide rails 21 are located along the sides of conveyor 1. As best shown in FIG. 9, a series of threaded studs 22, extend outwardly from each rail 21, and the studs extend through openings in brackets 23 which are pivotally connected to side walls 12 of frame 7 by hinges 24. The hinged connection permits the brackets 23 and guide rails 21 to pivot outwardly in the event a case has an enlargement in its width. The studs 22 are retained in position with respect to the brackets 23 by nuts 25 which are threaded on the studs 22 on either side of the brackets. The connection of the studs 22 to the brackets 23 provides an adjustment so that the guide rails 21 can be moved laterally of the conveyor.

The flap opening unit 3 includes a series of vertical supports 26 which extend upwardly from the conveyor frame 7 and the upper ends of vertical supports 26 are connected together by a series of longitudinal supports 27 and transverse supports 28 to provide a generally box-shaped framework. In addition, a transverse angle 29 is connected between corresponding pairs of vertical supports 26 at locations spaced from the upper ends of the supports 26 and an inverted V-shaped hood 30 is carried by the angles 29.

The flaps 31 of the case 2 may either be either partially open, fully spread, or closed as the case approaches unit 3. If the flaps 31 are in a spread position in which they extend laterally beyond the side walls of the case, a flap closing device is employed to pivot the flaps to a partially closed position in which they extend within the planes defined by the side walls of the conveyor. The flap closing device includes a pair of rods 32, and the upper ends 33 of rods 32 converge inwardly towards the longitudinal center of the conveyor and are secured to the under surface of the front end of the hood 30. Each rod 32 is provided with a reverse bend and the lower end 34 of each rod is attached to the forward end of the guide rails 21. If the flaps on the case extend laterally outward, as the case advances on the conveyor, the flaps will engage the rods 32 and will be deflected inwardly to a partially open position.

In the event the flaps 31 on the case are in a fully closed or locked position, a provision is made to release the flaps from this fully closed position. This mechanism is arranged to apply pressure to opposite side walls of the case, thereby causing the flaps to pivot inwardly to a partially opened position. The device for releasing the flaps from the fully closed position comprises two sets of rollers 36 with the sets being spaced above the side edges of the conveyor. As best illustrated in FIGS. 2 and 8, each roller is journaled on a vertical shaft 37 which is supported by a horizontal angle 38, and the angle 38 in turn is mounted on the ends of a pair of horizontal rods 39 which extend outwardly through openings in a horizontal angle 40. The horizontal angle 40 is supported by a pair of vertical angles 41 which are adjustably connected to the frame 7 of the unit.

To permit lateral movement of the rollers 36, the rods 39 extend through tubes 42 and nuts are threaded on the outer end of the rod. In addition, a coil spring 43 is located around each rod 39 and extends between the angle 38 and 40. The nuts provide a threaded adjustment for the position of the rollers and springs 43 act to urge the rollers inwardly against the sides of the case passing therebetween.

As the case passes between the two sets of rollers 36, the rollers engage the side walls of the case immediately beneath the upper edge of the case, thereby tending to deflect the side walls inwardly and causing the flaps to pivot or snap upwardly to a partially open position.

A pair of telescopic ducts 44 and 45 extend downwardly within the framework defines by the supports 26, 27, and 28, and are located to the rear of the rollers 36. As shown in FIG. 1, the lower or inner duct 45 is located within the lower end of the upper duct 44 and is movable relative to the outer duct. The lower end of the lower duct 45 is welded within an opening in a hood 30.

The annular space between the outer duct 44 and inner duct 45 is sealed by a foam plastic sealing member 46. The pressure differential between the outer surface of the sealing member 46 and the inner surface of the sealing member will cause the sealing member to become compressed against the inner duct 45 to thereby provide a relatively tight air seal between the sliding duct members.

As previously mentioned, the lower duct 45 is slidable with respect to ther upper duct 44 to vary the position of the lower duct 45 with respect to the cases 2 moving along the conveyor 1. To provide this vertical adjustment, the angles 29 are adjustably connected to the vertical supports 26, as best shown' in FIG. 2. The vertical supports 26 are each provided with an elongated slot 47 and studs 48 connected to angles 29 extend through the slots and receive nuts. With this construction, the angles 29 as well as the lower duct 45 can be adjusted vertically with respect to the vertical supports 26.

The control the flow of air into the ducts, a damper 49 is located in the upper duct 44. The upper end of the duct 44 is connected to a manifold 50 which in turn'is connected to the suction side ofa blower or fan, not shown.

The blower or fan creates a flow of air in the ducts 44 and 45 of sufficient intensity to raise the flaps 31 on the case 2 as the case is moved beneath the ducts. As shown in FIG. 3, the flaps are pivoted upwardly and bear against the under surface of the hood 30.

As the leading end of the case 2 moves beyond the hood 30 it contacts the flap spreading unit 4 which acts to spread the partially open flaps laterally outward. The flap spreading unit includes a generally boxlike framework composed of a series of vertical supports 51 which are secured to the side channels 12 of frame 7. The upper ends of the vertical support 51 are connected together by a pair of longitudinal supports 52 and a pair of transverse supports 53 to provide the framework.

The flaps 31 on the case 2, which are in a partially opened position, are spread outwardly so that they extend beyond the side walls of the container by a pair of spreading members or rods 54. The forward ends 55 of rods 54 are provided with U- shaped bends and are located on either side of the longitudinal center line of the conveyor. The central portions 56 of the rods 54 extend downwardly and outwardly and terminate in generally straight sections 57 which extend the length of the spreading unit 4. Rods 54 are supported from the framework by a series of U-shaped hangers 58. The inner end of each hanger is secured to the rods 54, while the outer end of the hanger is adjustably connected to vertical supports 51 by bolts 59 which extend through slots 60 in the vertical support.

As the case 2 advances beyond the hood 30, the rods 54 are received between the partially open flaps and as the case travels along the conveyor, the flaps are pivoted outwardly by the flared sections 56 of the rods and are held in the open position by the straight section 57, as best illustrated in FIG. 3.

In some instances, the case 2, in addition to having side flaps 31, may also be provided with end flaps and a provision is made to retain the end flaps in a closed position as the case passes through the flap spreading unit 4. The end flap holder is a generally L-shaped rod 61 having its upper end clamped between the free ends of a clamping ring 62 which is secured around the lower duct 45. End flap holder 61 is located along the center line of the conveyor and is provided with a diagonal section 63 which terminates in a generally horizontal section 64 which is located at approximately the same height as the open upper end as the case 2.

In addition to the end flap holder 61, a second end flap holder in the form of a plate 65 is employed and is located to the rear of the flap holder 61. As best shown in FIGS. 6 and 7, the forward end of plate 65 is provided with a reverse bend 66 which receives horizontal rod 67. A pair of studs 68 are secured to the rod and extend upwardly and are adjustably connected to a transverse bar 69. Bar 69 is mounted on a longitudinally extending channel 70 which extends between the supports 28 and 53. By threaded adjustment of the bolts 68 with respect to the bar 69, the vertical position of the plate 65 can be varied as desired.

The rear end of the plate 65 is secured to a hood 7], that is supported by a pair of transverse angles 72 connected to the vertical supports 51. To provide a vertical adjustment of the hood 71 with respect to the conveyor, the connection between the angles 72 and the vertical supports 51 comprises a series of studs 73 which extend through vertical slots 74 in the supports 51.

A pair of telescopic ducts 75 and 76, similar to ducts 44 and 45 extend downwardly within the framework defined by the supports 51, 52 and 53. The lower duct 75 is slidable vertically with respect to the upper duct 76 and the lower end of the lower duct is mounted within an opening in the hood 71. As

' described with respect to the ducts 44 and 45; the annular space between the upper and lower ducts 75 and 76 is sealed by a flexible foam rubber seal 77, similar to seal 46, previously described.

To control the flow of air into the ducts 75 and 76, a damper 78 can be located in the upper duct 76. The upper end of the duct 76 can be connected to manifold 50, or it can be attached to the suction side of a separate fan or'blower, not shown.

In operation, the cases 2 are successively introduced onto the forward end of the conveyor 1 and moved in the direction of the arrow. As the case approaches the unit 3, the rods 32 will engage the flap of the case, if the flaps are in a spread position, and pivot the flaps inwardly to a partially open position.

Further advancement of the case will move the case between the series of roller 36 and in the event the flaps 31 are in the fully closed position the pressure of the rollers against the side walls of the case will act to pivot the flaps upwardly to a partially open position. With the flaps partially open, the case will move beneath the duct 45 and the suction created in the duct will further pivot the flaps upwardly until they are in engagement with the sloping sides of the hood 30. As the case is advanced beyond the hood 30, the flaps spreading rods 42 are received between the partially opened flaps and the flared section 56 will pivot the flaps further outwardly to a location beyond the side walls of the case. The flaps will be held in this spread position by the straight section 57 of rods 54.

With the flaps held in the fully spread position, the case moves beneath the duct 76 where the suction created within the duct will act to draw lightweight debris, such as paper, straws, cigarette butts and the like from the open end of the case. A suitable filter can be included in the duct 76 to prevent the debris from being drawn into the fan or blower.

The case then moves along the conveyor to a station where the bottles are removed from the case.

The invention provides a continuous mechanism for automatically raising the flaps on the case or carton, spreading the flaps to a lateral position and removing lightweight debris from the case. As these functions are performed automatically in continuous sequence the labor cost which is normally associated with this operation is substantially reduced.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

We claim:

1. ln a conveying system for conveying containers having pivotable flaps enclosing the open upper end of the container, conveyor means to convey the container along a path of travel, first duct means having an inlet spaced above the conveyor means, first vacuum means for creating an upward flow of air in said first duct means of sufficient intensity to raise said flaps as the container moves beneath said duct means, flap spreading means spaced above the conveying means and located to the rear of said first duct means, in the direction of container travel, for spreading the flaps laterally beyond the side walls of the container, second duct means spaced above the conveyor means and located to the rear of said flap spreading means in the direction of container travel, said second duct means having an inlet spaced above the conveyor means, and second vacuum means connected to said second duct means for creating an upward flow of air in said second duct means of sufficient intensity to draw lightweight debris from the container as it passes beneath said second duct means.

2. The system of claim 1, and including flap holding means for holding the flaps in the spread position as the container passes beneath said second duct means.

3. The system of claim 1, wherein said first duct means comprises an upper duct member and a lower duct member with said duct members being telescopic with respect to each other, and means for adjusting the height of said lower duct member above said conveyor means.

4. The system of claim 3, and including a hood attached to the lower extremity of the lower duct member, the lateral extremities of said hood diverging downwardly and outwardly from said lower duct member.

5. The system of claim 3, and including means for sealing the space between said upper duct member and said lower duct member.

6. The system of claim 1, wherein said first duct means and said second duct means each comprises a fixed upper duct and a movable lower duct disposed in telescopic relation with said upper duct.

7. The system of claim 1, in which said flap spreading means extends longitudinally of the conveyor means and is disposed to be received between the open flaps, said flap spreading means having a pair of outwardly diverging wing members disposed to be engaged by the flaps and move the flaps laterally outward as the container travels along the conveyor means.

8. The system of claim 7, in which said wing members have generally curved lateral extremities disposed to be engaged by the flaps.

9. The system of claim 1, and including laterally adjustable guide means disposed along the side edges of the conveyor means for guiding the containers in movement on said conveyor means.

10. The system of claim 1, and including pressure means located ahead of the first duct means for applying pressure to the opposite sides of the container to thereby pivot the flaps from a closed position to a partiall open position.

11. The system of claim 10, w ereln said pressure means comprises a pair of rollers journaled about vertical axes and located in spaced relation on either side of the conveyor.

12. The system of claim 11, and including means for biasing one of the rollers of the pair toward the other roller of the pair.

13. The system of claim 10, wherein said pressure means comprises two sets of rollers, said sets being spaced horizontally and arranged to ride against the upper portions of the side walls of the containers.

14. The system of claim 10, and including means located ahead of the pressure means for engaging the flaps on the container in the event said flaps are open and pivoting the flaps inwardly to a partially closed position.

15. In a conveying system for conveying containers having flaps hinged to the side walls of the container and adapted to enclose the open top of said container, conveyor means to convey the container along a path of travel, pressure means for applying pressure to the opposite side walls of the container to pivot the flaps, if in the closed position, to a partially open position, first duct means located to the rear, in the direction of container travel, of the pressure means and having an inlet spaced above the conveyor means, first vacuum means for creating a pressure differential in said first duct means of sufficient intensity to raise said flaps as the container moves beneath said first duct means, flap spreading means spaced above the conveying means and located to the rear of said first duct means, for spreading the flaps laterally beyond the side walls of the container, said flap spreading means extending longitudinally of the conveyor means and disposed to be received between the open flaps, and including a pair of outwardly diverging members disposed to be engaged by the flaps and move the flaps laterally outward as the container travels along the conveyor means, second duct means spaced above the conveyor means, and located to the rear of said flap spreading means, said second duct means having an inlet spaced above the conveyor means, second vacuum means connected to said second duct for creating a pressure differential in said second duct means of sufficient intensity to draw lightweight debris from the container as it passes beneath the second duct means, and flap holding means for holding the flaps in the spread position as the container passes beneath said second duct means.

16. The system of claim 15, and including a hood connected to the lower end of said first duct means and extending forwardly to a location over said pressure means.

17. The system of claim 16, wherein said hood has a central longitudinally extending apex and inclined side walls diverging downwardly and outwardly from said apex, said flaps being pivoted upwardly into engagement with said inclined side walls of the hood.

18. The system of claim 15, and including end flap holding means located between said first and second duct means for engaging end flaps on the container and holding said end flaps in a closed position.

19. The system of claim 15, wherein said pressure means comprises two sets of rollers journaled about vertical axes, said sets being spaced horizontally and located along the respective side edges of the conveyor, each set arranged to ride against the upper portion of a side wall of the container. 

1. In a conveying system for conveying containers having pivotable flaps enclosing the open upper end of the container, conveyor means to convey the container along a path of travel, first duct means having an inlet spaced above the conveyor means, first vacuum means for creating an upward flow of air in said first duct means of sufficient intensity to raise said flaps as the container moves beneath said duct means, flap spreading means spaced above the conveying means and located to the rear of said first duct means, in the direction of container travel, for spreading the flaps laterally beyond the side walls of the container, second duct means spaced above the conveyor means and located to the rear of said flap spreading means in the direction of container travel, said second duct means having an inlet spaced above the conveyor means, and second vacuum means connected to said second duct means for creating an upward flow of air in said second duct means of sufficient intensity to draw lightweight debris from the container as it passes beneath said second duct means.
 2. The system of claim 1, and including flap holding means for holding the flaps in the spread position as the container passes beneath said second duct means.
 3. The system of claim 1, wherein said first duct means comprises an upper duct member and a lower duct member with said duct members being telescopic with respect to each other, and means for adjusting the height of said lower duct member above said conveyor means.
 4. The system of claim 3, and including a hood attached to the lower extremity of the lower duct member, the lateral extremities of said hood diverging downwardly and outwardly from said lower duct member.
 5. The system of claim 3, and including means for sealing the space between said upper duct member and said lower duct member.
 6. The system of claim 1, wherein said first duct means and said second duct means each comprises a fixed upper duct and a movable lower duct disposed in telescopic relation with said upper duct.
 7. The system of claim 1, in which said flap spreading means extends longitudinally of the conveyor means and is disposed to be received between the open flaps, said flap spreading means having a pair of outwardly diverging wing members disposed to be engaged by the flaps and move the flaps laterally outward as the container travels along the conveyor means.
 8. The system of claim 7, in which said wing members have generally curved lateral extremities disposed to be engaged by the flaps.
 9. The system of claim 1, and including laterally adjustable guide means disposed along the side edges of the conveyor means for guiding the containers in movement on said conveyor means.
 10. The system of claim 1, and including pressure means located ahead of the first duct means for applying pressure to the opposite sides of the container to thereby pivot the flaps from a closed position to a partially open position.
 11. The system of claim 10, wherein said pressure means comprises a pair of rollers journaled about vertical axes and located in spaced relation on either side of the conveyor.
 12. The system of claim 11, and including means for biasing one of the rollers of the pair toward the other roller of the pair.
 13. The system of claim 10, wherein said pressure means comprises two sets of rollers, said sets being spaced horizontally and arranged to ride against the upper portions of the side walls of the containers.
 14. The system of claim 10, and including means located ahead of the pressure means for engaging the flaps on the container in the event said flaps are open and pivoting the flaps inwardly to a partially closed position.
 15. In a conveying system for conveying containers having flaps hinged to the side walls of the container and adapted to enclose the open top of said container, conveyor means to convey the container along a path of travel, pressure means for applying pressure to the opposite side walls of the container to pivot the flaps, if in the closed position, to a partially open position, first duct means located to the rear, in the direction of container travel, of the pressure means and having an inlet spaced above the conveyor means, first vacuum means for creating a pressure differential in said first duct means of sufficient intensity to raise said flaps as the container moves beneath said first duct means, flap spreading means spaced above the conveying means and located to the rear of said first duct means, for spreading the flaps laterally beyond the side walls of the container, said flap spreading means extending longitudinally of the conveyor means and disposed to be received between the open flaps, and including a pair of outwardly diverging members dIsposed to be engaged by the flaps and move the flaps laterally outward as the container travels along the conveyor means, second duct means spaced above the conveyor means, and located to the rear of said flap spreading means, said second duct means having an inlet spaced above the conveyor means, second vacuum means connected to said second duct for creating a pressure differential in said second duct means of sufficient intensity to draw lightweight debris from the container as it passes beneath the second duct means, and flap holding means for holding the flaps in the spread position as the container passes beneath said second duct means.
 16. The system of claim 15, and including a hood connected to the lower end of said first duct means and extending forwardly to a location over said pressure means.
 17. The system of claim 16, wherein said hood has a central longitudinally extending apex and inclined side walls diverging downwardly and outwardly from said apex, said flaps being pivoted upwardly into engagement with said inclined side walls of the hood.
 18. The system of claim 15, and including end flap holding means located between said first and second duct means for engaging end flaps on the container and holding said end flaps in a closed position.
 19. The system of claim 15, wherein said pressure means comprises two sets of rollers journaled about vertical axes, said sets being spaced horizontally and located along the respective side edges of the conveyor, each set arranged to ride against the upper portion of a side wall of the container. 